Acceleration sensing devices for use in connection with machines which require monitoring and shutting down under certain conditions of operation are known in the prior art. Some examples of the patented prior art to which the present invention relates are U.S. Pat. Nos. 2,942,456; 3,448,228 and 3,641,290.
A need exists for a simpler, less expensive and more reliable acceleration sensing unit of the class shown in the above prior art patents, and it is the objective of this invention to satisfy this need. In accordance with the present invention, a shock and vibration responsive device employs an operating mechanism which embodies significantly fewer parts than comparable prior art devices. The invention has a fuller range of adjustability including a unique and simplified sensitivity adjustment of the armature carried by a spring-loaded lever arm in relation to an opposing stationary potted magnet. An improved soft rubber valve closure disc or seat adjustably mounted on the pivoted lever arm and resiliently biased toward the control fluid vent valve constitutes another key improvement over the prior art. An adjustable spring-loaded manual reset button for the device also serving as a visual trip indicator forms a further feature of the invention. Another important feature resides in an adjustable leveling stop for the pivoted lever arm assuring parallelism between the arm and the holding face of the potted magnet when the arm is latched in the vent valve closing position. A fluid pressure responsive remote resetting means for the pivoted lever, separate from the manual resetting button, is also provided on the unit.
Other features and advantages of the invention will become apparent during the course of the following description.